V/stol aircraft-by-pass engine having a double, thrust diverter valve assembly

ABSTRACT

A double, thrust diverter valve assembly for a by-pass engine applicable to the VTOL and V/STOL-types of aircraft and having a by-pass annulus and fan for directing the flow of bypass air thereinto, and in which an inflatable valve mechanism, operated from a compressed air source and mounted in a first, thrustaugmentation by-pass air flow-passage with a rearwardly-directed exhaust, is combined with a cascade valve mounted in a second, by-pass air flow-passage having a vertically-downward directed exhaust and thereby controlling the flow of by-pass air in the vertical flight mode.

United States Patent [1 1 Stevens V/STOL AiRCRAFT-BY-PASS ENGINE HAVINGA DOUBLE, THRUST DIVERTER VALVE ASSEMBLY [75] inventor: Emerson W.Stevens, Snyder, N.Y.

[73] Assignee: The United States of America as represented by theSecretary of the Air Force, Washington, D.C.

[22] Filed: Nov. 4, 1971 [21] Appl. No.: 195,601

[52] US. Cl. 244/53 R, 239/265.43, 239/265.29 [51] Int. Cl B64d 31/00[58] Field of Search 244/53 R, 52, 23 B, 244/23 D, 23 R, 12 B, 12 D, 12R;

[56] References Cited UNITED STATES PATENTS 3,482,804 12/1969 Pyptiuk;60/226 July 24, 1973 3,611,724 10/1971 Kutney 137/15.l 2,982,511 5/1961Connor 251/5 Primary ExaminerMilton Buchler Assistant Examiner-S. D.Basinger Attorney-Harry A. Herbert, Jr. et al.

[57] ABSTRACT A double, thrust diverter valve assembly for a by-passengine applicable to the VTOL and V/STOL-types of aircraft and having aby-pass annulus and fan for directing the flow of bypass air thereinto,and in which an inflatable valve mechanism, operated from a compressedair source and mounted in a first, thrust-augmentation by-pass airflow-passage with a rearwardly-directed exhaust, is combined with acascade valve mounted in a second, by-pass air flow-passage having averticallydownward directed exhaust and thereby controlling the flow ofby-pass air in the vertical flight mode.

1 Claim, 7 Drawing Figures V/S'IOL AIRCRAFT-BY-PASS ENGINE HAVING ADOUBLE, TIIRUST DIVER'IER VALVE ASSEMBLY BACKGROUND OF THE INVENTIONThis invention relates generally to the application of the by-pass orturbofan engine to VTOL and/or V/STOL aircraft and, in particular, to animproved thrust diverter valve assembly therefor.

Because of the faster speeds and therefore landing and takeoff distancesrequired for the more or less conventional types of jet aircraft, therehas been a growing interest in, and development for many years of boththe vertical-takeoff-and-landing (VTOL) aircraft and theshort-takeoff-and-landing (STOL) aircraft. Many forms of the VTOLaircraft have STOL characteristics and therefore may be properlyreferred to as a V/STOL aircraft. Of course, concurrent with thedevelopment of the aircraft itself has been the simultaneous or almostsimultaneous development of a suitable power plant. Basically, fourgeneral types of VTOL and V/STOL propulsion systems have been generallyproposed; namely, the rotor, propeller, ducted fan and turbojet enginesystems. In this connection, the turbofan or, bypass engine, as it isreferred to hereinafter in connection with the present disclosure, isproperly considered as being a modified turbojet rather than a ductedfantype engine. In the usual type of turbofan or by-pass engine, theprimary thrust created by the exhaust of hot combustible products fromthe main, turbojet engine portion may be augmented, as is well-known, bythe provision of a flow of bypass or secondary air through a bypass,annular passage or chamber concentrically arranged to the main engine.The circumferential portions of a fan member, mounted just forward of,or integrated with the engine compressor section, are used to and indirecting this bypass or secondary air flow into the bypass passage orchamber. With such a bypass passage arrangement, the propulsiveefficiency of the pure turbojet engine is greatly increased in therelatively low speed ranges and is, therefore, particularly applicableto the VTOL, STOL and V/STOL-types of aircraft. Accordingly, the usualby-pass engine has been modified, in accordance with the teachings ofthe present invention, to be described hereinafter, for particularapplication to VTOL and/or V/STOL aircraft, by the incorpo ration of adual-annular passage system that includes a VTOL outlet for vertical orsubstantially vertical flight. In this connection, the present inventionconstitutes a further development and improvement of previouslyconceivedby-pass engines described and claimed by the present applicant incopending patent application Ser. No. 77,776, filed Oct. 5, ,1970, nowU.S. Pat. No. 3,660,981 on an invention entitled, The V/STOL Aircraft",and patent application, Ser. No. 193,436, filed Oct. 28, I971, on aninvention entitled, By-Pass Engine Having a Single, Thrust DiverterValve Mechanism for a V/STOL Aircraft". The improvement of the presentinvention will appear self-evident hereinafter in the following summaryand detailed description thereof.

SUMMARY OF THE INVENTION This invention consists briefly in an improvedthrust diverter means for a bypass engine having a main,thrust-producing turbojet engine portion, a by-pass annulus surroundingthe main, turbojet engine portion, a fan for directing a by-pass orsecondary air flow into the inlet of the by-pass annulus, a pair ofannular flow passages surrounding the turbojet engine portion and inrespective communication with the outlet of the bypass annulus, andrespectively incorporating rearwardly and vertically downwardly-directedexhaust passage means for either augmenting the forward thrust of themain engine portion, or to convert the engine to thevertical-takeoff-and-landing configuration. The said thrust divertermeans includes a dual arrangement consisting of a cascade orvenetian-blind type of valve assembly adjustable to an open or closedposition within the annular passage having the verticallydownwardly-directed exhaust means, and an inflatable valve assembly inunique combination therewith, and adjustable either to an inflated ordeflated position within the other annular passage to thereby controland thus provide thrust-augmentation to the main engine portion duringthe. forward flight mode of engine operation.

Certain advantages, as well as objects, of the present invention willbecome readily apparent hereinafter from the following disclosurethereof, taken in connection with the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional andpartly schematic view, illustrating the overall configuration of oneform of bypass engine in which the improved double, thrust divertervalve assembly of the present invention may be applied;

FIG. 2 is a broken-away, partly schematic and crosssectional view, takenabout on line 2-2 of FIG. 1, showing details of the cascade or venetianblind-type of valve mechanism forming part of the inventive double,thrust diverter valve assemblyand controlling the flow of secondary orby-pass air through the vertical flight mode-outlet of the presentengine;

FIG. 3 is a second broken-away view, partly schematic in form andlooking in the direction of the arrow A in FIG. 1 to illustrateadditional details of the eascade or venetian blind-type of valvemechanism of FIG.

FIG. 4 is a-relatively enlarged, partly broken-away and fragmentaryview, illustrating details of the novel inflatable valve mechanism ofthe present assembly, which valve mechanism has been generally indicatedas being positioned in the present by-pass engine at the area marked Bin FIG. 1;

FIG. 5 is another relatively enlarged, partly brokenaway and fragmentaryview, showing still further details of the inflatable valve mechanism ofFIG. 4;

FIG. 5a is an additional partly schematic and crosssectional view, moreclearly showing one form of bleed air inlet and vent member used tocontrol the inflation and deflation of the inventive inflatable valvemember; and

FIG. 6 represents still another relatively enlarged, partly broken-awayand fragmentary view, more clearly illustrating the attachment meansbetween the inflatable valve mechanism of FIGS. 4 and 5 and the wall ofthe by-pass passage or chamber in which it is mounted.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring particularly to FIG. 1of the drawings, a by; pass fan-type of turbojet engine in which theimprovement'of the present invention may be applied is indicatedgenerally at 10 as including, in part, an inner shell 11, and an outershell 12 between which is formed a bypass annulus at 13. A diffusermember at 14 may be positioned in the by-pass annulus 13 for the usualpurpose. Enclosed within the inner shell 11 may be positioned a pureturbojet engine portion comprising the compressor section that includesthe main, compressor support-member at 15 and the plurality ofalternatelydisposed stator and rotor blade elements at 16, a turbine at17, a rotatable shaft 18 on the opposite end portions of which may berigidly supported the compressor support-member 15 and turbine 17, apair of combustion chambers 19 and 20, and an exhaust or tail pipesection at 21.

A fan 23 may be mounted forwardly of, and for simultaneous rotationwith, the compressor supportmember 15, as by means of the stub shaft at22. As clearly shown, the circumferential portions or periphery of thefan 23 extend in an overlapping relation to the inlet of the bypassannulus 13, so that rotation of the fan 23 acts to positively direct aflow of by-pass or secondary air into the said bypass annulus l3.Naturally, as in the usual by-pass-type of turbojet engine, a primaryflow of air passes through the inlet of the compressor section 15, 16and is thereafter directed downstream, in compressed form, forsubsequent mixture and ignition with a supply of fuel in the combustionchambers 19 and 20. The hot products of combustion therefrom are thenexhausted against the turbine 17, which then acts, through the shaft 18,to drive the compressor 15, 16. Of course, in other modifications of theby-pass engine, a two-spool compressor and a separate turbine fordriving the fan 23 could be easily utilized without departing from thetrue spirit or scope of the invention. In any event, the hot combustibleproducts, after having a portion of the energy thereof utilized fordriving the compressor, are exhausted out the tail pipe section 21 tothereby provide the principal forward thrust of the engine.

The previously-described flow of bypass or secondary air entering theby-pass annulus 13 under the urging of the fan 23 may, in accordancewith the unique teaching of the present invention, alternately passinto, and through one of two communicating, annular flow passages orchambers, indicated respectively at 24 and 26, and each of whichincorporate inlet portions in open communication with the outlet fromsaid by-pass annulus 13, at a different angular relation therewith, andwhich are further arranged in concentric relation relative to each otherand to the main, turbojet engineportion. Annular passage or chamber 24,which may be relatively elongated in form, incorporates arearwardlydirected exhaust, indicated generally at 24a, that, in theforward flight mode of engine operation, permits the by-pass orsecondary air to flow in the direction indicated by the broken arrows at25 for its exhaustion in a rearward direction out the said exhaust 24ato thereby augment the forward thrust being developed in the main,turbojet engine portion.

For the vertical flight mode of engine operation, thepreviously-referred to annular passage or chamber 26, which is arrangedfurther outwardly of, and in concentric relation to, the annular passageor chamber 24, may be relatively enlarged in configuration andincorporate a vertical-takeoff-and-landing (VTOL) outlet opening,indicated generally at 28, which outlet opening 28 is naturally orientedin a vertically-downward direction to thereby direct the flow of bypassor secondary air entering the bypass annulus 13 in the directionindicated by the solid arrows at 27.

To provide for the alternate flow of bypass or secondary air from thebypass annulus 13 to one or the other of the annular chambers 24, 26,the new and improved double, thrust diverter valve assembly of thepresent invention may be installed in the previously-described by-passengine. The said double, thrust diverter valve assembly consists, inpart, ofa first, cascade or venetian blind-type of valve mechanism,indicated generally at the reference numeral 29 in both FIGS. 2 and 3 asbeing mounted in the VTOL-outlet opening 28. The mechanism 29 consistsof a plurality of individual vane elements at 30 that are mounted forcollective rotation between the opened position, shown in solid lines inFIG. 2, and the closed position of FIG. 3 to thereby completely blockthe flow of bypass or secondary air through the said VTOL-outlet opening28. As seen in the latter figure, said vane elements 30 extend clearacross outlet opening 28 and may be each rotatably mounted about acentral axis, as shown at the reference numeral 29a, for example, whichaxis may be extended to opposite sides of the engine wall surfaces 31and 32 incorporated within the present engine and forming the saidoutlet opening 28 therebetween. Of course, the vane elements 29 may beeach attached, for example, to a relatively elongated, common rack lever(not shown) or to other suitable operating means, that may be engaged,for example, with a pinion gear mounted on the drive shaft of a motorunder control of the aircraft pilot, copilot or other aircrew member.However, the specific operating means for rotating the vane elements 30are not illustrated, since the specific details thereof are unimportantto the present invention.

In unique combination with the aforementioned first, cascade or venetianblind-type of valve mechanism, as at 29, that is utilized to control thevertical-takeoffand-landing (VTOL) flight mode of engine operation, is asecond, combined nozzle and valve mechanism, indicated generally at 33in FIGS. 1, 4 and 5, which second, valve mechanism 33 is shown mountedin the previously-referred to first, relatively elongated, bypass orsecondary air flow-passage or chamber 24 adjacent the exhaust 24athereof for thereby controlling the bypass or secondary air flowrepresenting the forward thrust-augmentation flight mode of engineoperation. For the latter purpose, the said second, combined nozzle andvalve mechanism 33 uniquely consists of an inflatablenozzle/valve-diaphragm member 34, preferably made of a silicone rubberor, alternatively, it may be constructed from any other suitableinflatable material. In operation, said diaphragm member 34 is designedto be inflated from its relaxed or deflated condition, shown at thesolid line position indicated at the said reference numeral 34, to theinflated condition, illustrated in dashed lines at 34a, which inflatedcondition, at 34a, acts, and is sufficient to completely block andseal-off the said first, bypass or secondary air flowpassage or chamber24 so that no air will pass therethrough.

As is seen particularly in FIG. 6, for example, the periphery orcircumferential portion of the aforementioned novel, combined,inflatable nozzle and valvediaphragm member 34 may be rigidly supportedand affixed to the outer surface of the inner shell 11 as by means of acombined diaphragm member-attaching and supporting means, indicatedgenerally at 35 as consisting, in part, of a ring-like retainer elementat 36 that is positioned on top of the diaphragm memberperiphery orcircumferential portion. The latter may be bonded to the ring-likeretainer element 36 in any suitable manner, and the said ring-likeretainer element 36, together with the diaphragm member-periphery orcircumferential portion may, in turn, be collectively rigidly affixed tothe inner shell 11, as by means of the bolt-attachment at 37 (Note FIG.5). To provide further reinforcement and a more stable attachment, forthe bolt-attachment 37,.the combined attaching and supporting means 35further includes a reinforcing back support member, as depicted at 38 inFIG. 6, to which the said bolt-attachment 37 may also be affixed.

To provide for the necessary inflation of the, diaphragm member 34, whenit is desired to perform the VTOL mode of operation of the presentengine, a source of compressed gas, such as air, may be supplieddirectly into the compartment 39, formed by the inflation of andenclosed within the inflated member 34, through a small opening, as seenat 40 in FIG. 6, for example, by means of a conduit 41, controlled by avalve at 42, connected to a suitable compressed air supply,

such as that provided by the engine-compressor itself. Thus, compressorbleed air may be used for this purpose and, to this end, aninflate/deflate line comprising the internally-threaded and openpassage-fixture element, seen at 43 in FIGS. 4 and 5a, may be mounted inthe opening 40 that has been formed'in the wall of the inner shell 11,as has been previously described in specific connection with FIG. 6.Said inflate/deflate line or fixture element 43may be internallythreaded and an externally threaded bleed air inlet and vent member,depicted at the'reference numeral 44 in FIGS. 5 and 50, may beadjustably position ed therewithiri. As seen in the aforesaid FIGS. 5and 5a, in one form thereof, the bleed air inlet and vent member 44 maybe of an L-shaped or elbow configuration and it further incorporates anair passage or chamber at 45 that is open at 'both ends. Thus, coolingair, constituting the engine compressor bleed air and flowing in thedirection of the arrow indicated at 46 in the said FIGS. 5 and 5a; wouldnaturally enter the inlet of the air passage or chamber 45 (Note FIG.5a) where it would pass through and act upon, and thereby causeinflation of the previously-described nozzle/valve-diaphragm member 34to the dashed line position illustrated at 34a in FIGS. 1, 4 and 5. Thelatter position, of course, blocks the flow of bypass or secondary airthrough the annular passage 24. Of course, when it is desired to deflatethe said diaphragm member 34 it isonly necessary to stop the flow of thecompressor bleed air into the chamber 39 formed by the inflatedcondition of the diaphragm member 34, and then provide for the ventingof the compressed airfrom the chamber 39. Naturally, many differenttypes of available valve control mechanisms could be used for thispurpose without departing from the true spirit or scope of theinvention. In the schematic and cross-sectional view of FIG. 5a, oneform of control means for the diaphragm member 34 has been depicted.Thus, the mechanism provided in this arrangement consists ofincorporating a stub shaft 51 extending from the bottom of the bleed airinlet and vent member 44, with a gear 47 shown affixed thereto andengaged with a pinion 48 mounted, in turn, on the drive shaft 49 of anelectrical motor 50, which may be under control of the pilot or otheraircrew member. Thus, op-

eration of the motor 50 would result in the rotation of the bleed airinlet and vent member 44 from a first position shown in FIGS. 5 and 5a,wherein its inlet opening is facing directly in an upstream direction tothereby receive the compressed, engine compressor air directlythereinto, to a second position oriented at an angle of 180 to its firstposition and thereby facing directly downstream. With the latterorientation, it is obvious that no compressed air would flow into, andthrough the bleed air passage or chamber 45 to act upon and inflate thediaphragm member 34. On the contrary, the rapid flow of compressed airpassed the bleed air inlet and vent member 44, which is now facingdirectly downstream, would cause a suction or negative pressure,resulting in the venting of compressed air in the compartment 39 throughthe said air passage or chamber 45, and thus the diaphragm member 34would return to its deflated or solid line position of FIG. 5, forexample, to open the annular passage or chamber 24.

To summarize the operation of the present invention, for the forwardflight mode, the first, rotating cascade or venetian blind-type of valvemechanism 29 would be closed to the position indicated in FIG. 3, forexample, and the nozzle/valve-diaphragm member 34 would be tion. Thus,the by-pass or secondary air flow in the annular passage or chamber 26would be blocked, and itsflow through the passage or chamber 24permitted to thereby provide thrust-augmentation to theprincipal forwardthrust being developed by the main, turbojet engine portion. For thevertical flight mode, the aforesaid diaphragm member 34 would beinflated, as for example, in the manner previously described, to thedashed line position of FIG. 5, for example, to thereby block the flowof bypass or secondary air through the annular passage or chamber 24,and the cascade or venetian blind-type of valve mechanism 29 would beopened to thereby provide forthe flow of bypass or secondary air throughthe annular passage or chamber 26 for exhaustion out thevertically-downwardly-directed outlet opening 28 to thus create verticalthrust.

I claim:

1. A by-pass engine comprising; a main, forward thrust-producingturbojet engine-portion including compressor, turbine and main exhaustsections for seting on, and producing the main, forward thrust of theengine from the hot combustible products of the mixture of fuel and aprimary air flow there-through; a combined, forward thrust-augmentationand verticaltakeoff-and-landing thrust-producing portion including aby-pass annulus formed in concentric relation to, and between the casingof, said turbojet engine-portion, constituting an inner shell element,and an outer shell element, and having an upstream or inlet end portionopen to the main air inlet of the engine and a fan for pressurizing,converting, and alternately directing and ing of; a first, by-pass orsecondary air flow-passage means disposed in concentric and surroundingrelation relative to, and immediately outwardly of, said turbojetengine-portion and having a first, inlet end-passage portion inopeneommunication with an upstream portion of said by-pass annulus forthereby receiving bypass or secondary air flow therefrom, and a first,ex-

haust means incorporating a relatively narrow and arcuate-shaped,valve-outlet end passage portion, and further communicating and forminga first, substantially straight-through and horizontally-oriented flowpath-passage with said first, inlet end-passage portion and the upstreamportion of said by-pass annulus for thereby exhausting the by-pass orsecondary air flow in a rearward direction substantially augmenting themain, forward thrust being produced by the said turbojet engine-portion;a second, separate by-pass or secondary air flow-passage means disposedin concentric relation further outwardly of said first-named passagemeans and having a second, inlet end-passage portion in opencommunication with the upstream portion of said bypass annulus at anangle to said first, inlet endpassage portion of said first-namedpassage means for thereby receiving by-pass or secondary air flowtherefrom, and a second, exhaust means in communication and forming avertically downwardly-directed flow path-passage with said second, inletend-passage portion and the upstream portion of said by-pass annulus forthereby exhausting the bypass or secondary air flow in avertically-downward direction representing thevertical-takeoff-and-landing mode of engine operation; and combinedmeans for alternately and selectively directing the by-pass or secondaryair flow entering said by-pass annulus into one or the other of saidfirst and second-named, by-pass or secondary air flow-passage means tothereby either augment the main, forward thrust being produced in theengine, or to establish the vertical-takeoff-and-landing configurationthereof; said means comprising; a first, forward thrust-augmentationmechanism mounted for operation between open and closed positions in andthereby blocking and thus controlling the flow of by-pass or secondaryair into, and through said first, by-pass or secondary air flow passagemeans representing the forward thrustaugmentation mode of engineoperation; and a second vertical thrust-producing mechanism mounted, andadjustable to open and closed positions within said second, bypass orsecondary air flow-passage means to thereby control the flow of by-passor secondary air through said second, separate air flow-passage meansand second, vertically downwardly-oriented, exhaust means representingthe vertical-takeoff-and-landing mode of engine operation; said combinedmeans for alternately and selectively directing the by-pass or secondaryair flow into one or the other of said first and second-named by-pass orsecondary air flow-passage means comprising a double, thrust divertervalve assembly including a first, rotatable cascade valve consisting ofa plurality of individual vane elements arranged in a venetianblind-type configuration and mounted for rotation between open andclosed positions within said second, vertically downwardlyoriented,exhaust means, adjacent to the outlet therefrom; a second, elasticdiaphragm-valve mounted within said first, horizontally-oriented,by-pass or secondary air flow-passage means at the relatively narrow andarcuate-shaped, valve-outlet end passage portion thereof, and adjustableby expansion between a first, inner, non-expanded and inoperativeposition adjacent to the inside diameter-surface of said arcuate-shaped,valve-outlet end passage portion, and a second, outer, expanded andoperative, sealed position against the outside diameter-surface, andthereby precisely accommodating the arucate-shaped configuration of, andthus completely blocking said valve outlet end passage portion;compressed gas means communicating with, andthereby effective to inflatesaid second, elastic diaphragm-valve from its first, inner position toits second, outer expanded and operative position; and a combined,releasable mounting and supporting means for rigidly attaching theperipheral portion of the said second, elastic diaphragm-valve to thesaid inner shell element on the inside diameter-surface of the saidrelatively narrow and arcuate-shaped, valve-outlet end passage portion,and thereby positively providing for the outward inflation of the main,intermediate portion of the elastic diaphragm of the said second-named,valve into its expanded position against the outer diametersurface ofsaid last named, valve-outlet end passage portion; said valve-mountingand supporting means comprising; a ring-like element bonded to, andoperative to rigidly maintain, said second, elasticdiaphragm-valve-peripheral portion in sealed relation against the outersurface of said arcuate-shaped, inner shell element; a rigid,reinforcing back support member bonded to the inside surface of saidinner shell element at a location thereat in direct alignment with, andthereby providing positive reinforcement to the said ring-like elementand said valve-peripheral portion; and quick-releasable, bolt-attachmentmeans for rigidly and releasably interconnecting said ring-like elementto said elastic diaphragm-valve-peripheral portion and said reinforcingback support member for thereby both positively providing a rigid clampon the said peripheral portion and simultaneously facilitating thedisassembly and replacement thereof.

i ns s s

1. A by-pass engine comprising; a main, forward thrust-producingturbojet engine-portion including compressor, turbine and main exhaustsections for acting on, and producing the main, forward thrust of theengine from the hot combustible products of the mixture of fuel and aprimary air flow there-through; a combined, forward thrust-augmentationand vertical-takeoff-and-landing thrust-producing portion including aby-pass annulus formed in concentric relation to, and between the casingof, said turbojet engine-portion, constituting an inner shell element,and an outer shell element, and having an upstream or inlet end portionopen to the main air inlet of the engine and a fan for pressurizing,converting, and alternately directing and dividing a portion of theincoming air constituting a by-pass or secondary air flow, initiallyentering the said upstream or inlet end portion of said by-pass annulus,into one or the other of two flow paths respectively consisting of; afirst, by-pass or secondary air flow-passage means disposed inconcentric and surrounding relation relative to, and immediatelyoutwardly of, said turbojet engine-portion and having a first, inletend-passage portion in open communication with an upstream portion ofsaid by-pass annulus for thereby receiving by-pass or secondary air flowtherefrom, and a first, exhaust means incorporating a relatively narrowand arcuate-shaped, valve-outlet end passage portion, and furthercommunicating and forming a first, substantially straight-through andhorizontally-oriented flow path-passage with said first, inletend-passage portion and the upstream portion of said by-pass annulus forthereby exhausting the by-pass or secondary air flow in a rearwarddirection substantially augmenting the main, forward thrust beingproduced by the said turbojet engine-portion; a second, separate by-passor secondary air flow-passage means disposed in concentric relationfurther outwardly of said first-named passage means and having a second,inlet end-passage portion in open communication with the upstreamportion of said bypass annulus at an angle to said first, inletend-passage portion of said first-named passage means for therebyreceiving by-pass or secondary air flow therefrom, and a second, exhaustmeans in communication and forming a vertically downwardly-directed flowpath-passage with said second, inlet end-passage portion and theupstream portion of said by-pass annulus for thereby exhausting thebypass or secondary air flow in a vertically-downward directionrepresenting the verticaltakeoff-and-landing mode of engine operation;and combined means for alternately and selectively directing the by-passor secondary air flow entering said by-pass annulus into one or theother of said first and second-named, by-pass or secondary airflow-passage means to thereby either augment the main, forward thrustbeing produced in the engine, or to establish thevertical-takeoff-and-landing configuration thereof; said meanscomprising; a first, forward thrust-augmentation mechanism mounted foroperation between open and closed positions in and thereby blocking andthus controlling the flow of by-pass or Secondary air into, and throughsaid first, by-pass or secondary air flow-passage means representing theforward thrustaugmentation mode of engine operation; and a secondvertical thrust-producing mechanism mounted, and adjustable to open andclosed positions within said second, bypass or secondary airflow-passage means to thereby control the flow of by-pass or secondaryair through said second, separate air flow-passage means and second,vertically downwardly-oriented, exhaust means representing thevertical-takeoff-and-landing mode of engine operation; said combinedmeans for alternately and selectively directing the by-pass or secondaryair flow into one or the other of said first and second-named by-pass orsecondary air flowpassage means comprising a double, thrust divertervalve assembly including a first, rotatable cascade valve consisting ofa plurality of individual vane elements arranged in a venetianblind-type configuration and mounted for rotation between open andclosed positions within said second, vertically downwardlyoriented,exhaust means, adjacent to the outlet therefrom; a second, elasticdiaphragm-valve mounted within said first, horizontally-oriented,by-pass or secondary air flow-passage means at the relatively narrow andarcuate-shaped, valve-outlet end passage portion thereof, and adjustableby expansion between a first, inner, non-expanded and inoperativeposition adjacent to the inside diameter-surface of said arcuate-shaped,valve-outlet end passage portion, and a second, outer, expanded andoperative, sealed position against the outside diameter-surface, andthereby precisely accommodating the arucate-shaped configuration of, andthus completely blocking said valve outlet end passage portion;compressed gas means communicating with, and thereby effective toinflate said second, elastic diaphragm-valve from its first, innerposition to its second, outer expanded and operative position; and acombined, releasable mounting and supporting means for rigidly attachingthe peripheral portion of the said second, elastic diaphragm-valve tothe said inner shell element on the inside diameter-surface of the saidrelatively narrow and arcuate-shaped, valve-outlet end passage portion,and thereby positively providing for the outward inflation of the main,intermediate portion of the elastic diaphragm of the said secondnamed,valve into its expanded position against the outer diameter-surface ofsaid last named, valve-outlet end passage portion; said valve-mountingand supporting means comprising; a ring-like element bonded to, andoperative to rigidly maintain, said second, elasticdiaphragm-valve-peripheral portion in sealed relation against the outersurface of said arcuate-shaped, inner shell element; a rigid,reinforcing back support member bonded to the inside surface of saidinner shell element at a location thereat in direct alignment with, andthereby providing positive reinforcement to the said ring-like elementand said valveperipheral portion; and quick-releasable, bolt-attachmentmeans for rigidly and releasably interconnecting said ring-like elementto said elastic diaphragm-valve-peripheral portion and said reinforcingback support member for thereby both positively providing a rigid clampon the said peripheral portion and simultaneously facilitating thedisassembly and replacement thereof.